Brand: HydraPak
Category: Running Water Filtration & Treatment
Recommended by Spencer Imbach, Trail Runner & Snowboarder — Baltimore, MD
The UltraFlask™+ Filter Cap is an innovative filtration solution designed for runners, allowing them to enjoy clean, fresh water on-the-go. Its lightweight design and high-flow valve make hydration effortless during any outdoor activity. 1. Compatible with all HydraPak 42mm running flasks and handhelds for seamless integration. 2. High-flow Blaster valve enables quick and easy sipping without the need to stop. 3. Effectively removes 99.999% of E.coli and 99.9999% of parasitic cysts, ensuring safe drinking water. 4. Lightweight and compact design makes it easy to carry without adding bulk. 5. Traditional bite valve and cap design for familiar and convenient usage. 6. Durable construction ensures long-lasting performance in rugged conditions. 7. Backed by a Beyond Lifetime Guarantee, reflecting the brand's commitment to quality. The UltraFlask™+ Filter Cap is ideal for trail runners, hikers, and outdoor enthusiasts seeking reliable hydration solutions. It performs best in remote environments where clean water sources may be scarce, making it perfect for long-distance runs, backpacking trips, or day hikes. This product is suitable for users of all skill levels, providing peace of mind while enjoying nature.
Price: $43
- Who it's for
- Trail runners, ultrarunners, and field workers who need to refill from natural water sources without carrying heavy filtration gear. Works well for long days where pre-stashing water isn't practical.
- What people are saying
- Hosts consistently praise the minimal weight, ease of use, and ability to grab water on the go from streams and natural sources. The locking mechanism gets specific callouts for preventing leaks when stored in a vest or belt.
- Worth noting
- Compatible with most flasks, not just HydraPak bottles. The straw cap variant is noted as particularly useful for drinking from front-pack bottles without craning your neck during races.
Frequently asked questions
Who is the UltraFlask™+ Filter Cap for?
Trail runners, ultrarunners, and field workers who need to refill from natural water sources without carrying heavy filtration gear. Works well for long days where pre-stashing water isn't practical.
What do experts say about the UltraFlask™+ Filter Cap?
Hosts consistently praise the minimal weight, ease of use, and ability to grab water on the go from streams and natural sources. The locking mechanism gets specific callouts for preventing leaks when stored in a vest or belt.
What should you know before buying the UltraFlask™+ Filter Cap?
Compatible with most flasks, not just HydraPak bottles. The straw cap variant is noted as particularly useful for drinking from front-pack bottles without craning your neck during races.
More from Spencer Imbach's Long Run
View Spencer Imbach's expert gear recommendations on Rendezvu
What other hosts are saying
13 experts recommend the HydraPak UltraFlask™+ Filter Cap.
Ultralight water filter that conveniently connects right to your HydraPak soft flasks!
Recommended in Fastpacking
John Bruno, Ultra trail-runner, ski mountaineer
Self explanatory: Big thing here is that it locks so I can filter water and put it in a pack or a belt and not soak my kit.
Recommended in High Alpine Running
Tyler Sarkisian, Endurance / Strength Athlete + Coach
carry 1-2 with me so I can always find water. filters just about anything.
Recommended in Trail Run
I try to treat my water from natural sources in almost all areas that I’m exploring. These filters are simple and quick to use with minimal added weight to a regular soft flask.
Recommended in Mountain Running Safety Gear
This thing is unreal. Saves you so much weight. Grab water from anywhere.
Recommended in Canyons 100
Makena Morley, Professional Runner (Roads, Trails...)
Absolutely love this filter - it fits on most bottles and is so nice to bring along so I can refill all my bottles on a longer training day when I don't stash aid at my car or house! And you can drink out of it and not worry about getting Giardia!
Recommended in Hydration while running
Compatible with most flasks. Great tool for the trail runners tool kit when you want to go farther.
Recommended in Trail gear I actually use
Jamie Hunyor, Ultrarunner & field botanist
I have two of these—one for long days on the trails in my belt or pack and another in my field bag for going off-trail in my day job as a botanist in the Sierra Nevada. On the trails it saves weight so I can carry less & still stay hydrated. At work, it gives me peace of mind knowing that if something happens & I run out of the water I’m carrying in my pack, I’ll be able to fill from the streams in my survey area.
Recommended in Botany fieldwork gear
These let me use my front pack bottles without craning my neck - They stow nicely out of the way in the Tantrums vest. It's not much, but after 4 hours of bending your neck to drink water, it's the little things.
Recommended in Dirt Run Essentials
Allison Powell, Ultrarunning Coach, Ultrarunning Communnity Leader
This cap was easy to add on to HydraPak bottles and allowed me to simply fill water and go!
Recommended in Tahoe-Yosemite FKT
Joe Corcione, Ultrarunning Athlete + Coach
With a lot of water on the course, I'll be using this filter cap to fill up some on the go!
Recommended in Western States 100M Gear I'll Be Using
Straw caps make drinking so much easier while racing.
Recommended in Run Rabbit 100
